Cementitious Barrier Partnership

Program Update

Interagency Steering Committee on Performance and Risk Assessment

Community of Practice Annual Technical Exchange Meeting

Richland, Washington

December 15-16, 2015

Project Team MembersVanderbilt University & CRESP D. Kosson*, K.G. Brown*, A.C. Garrabrants, S. Mahadevan, J. Branch, F. Sanchez

Savannah River National Laboratory (SRNL)C. Langton*; G. Flach*; H. Burns*; R. Seitz, S. Marra; F.G. Smith, III

Energy Research Centre of The Netherlands (ECN) & CRESPH. van der Sloot (HvdS Consultancy), J.C.L. Meeussen (NRG), P. Seignette (ECN)

National Institute of Standards and Technology (NIST)K. Snyder, J. Bullard, P. Stutzman

Nuclear Regulatory Commission (NRC) D. Esh, J. Phillip, M. Furman

SIMCO Technologies, Inc. (Canada)E. Samson, J. Marchand

*Project Leadership Team

DOE-EM Project Manager: Pramod Mallick2

• Need: Mechanistic modeling tools and supporting lab and field data to build confidence in the prediction of long-term performance for unique DOE cementitious barriers and waste forms.

• CBP Response:– Developed software based on mechanisms (phenomena) to predict long-term

cementitious material behavior to sulfate/chloride attack, carbonation/oxidation, and leaching

– Conducted Integrated Experimental Programs combining both modeling and experimental data for model parameterization and validation

• CBP Priorities– Support DOE Performance Assessments (Hanford and Savannah River Sites)

– Support Software Quality Assurance for user to meet NQA-1/DOE O 414.1

– Technetium-99 mobility

• Technical Strategy / Approach– Reference cases for unique DOE cementitious materials

– Test bed exposure studies to study behavior of DOE cementitious materials

– Extension/enhancement of existing tools – STADIUM, LeachXS/ ORCHESTRA, GoldSimPerformance Assessment (PA) framework

– Integrated experimental and modeling programs

CBP Support of Tank Waste Challenges

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Example Key Question, Variables, & Processes

• Key Question– What is the rate of release for radionuclides and chemical contaminants from

cementitious wasteforms (e.g., Cast Stone) under a range of PA scenarios?

• Material Variables– Composition (major contaminants, radionuclides, contaminant loadings)

– Physical properties (porosity, strength, density)

– Intrinsic leaching characteristics (liquid-solid partitioning, reducing capacity, liquid and gas phase effective diffusion coefficients/tortuosity)

• Scenario Variables– Physical configuration and initial/boundary conditions

– Water – Saturation, infiltration rate and frequency

– Cracking – Initial state, long-term

• Important Aging Processes– Initial hydration and material state (including cracking)

– Sulfate attack (liquid phase) → cracking and release

– OxidaGon (predominantly through gas phase transport) → release

– Carbonation (predominantly through gas phase) → pH effect/cracking/release

– Leaching of wasteform primary consGtuents → pH effect

– Microstructure changes (mineralogy, pore structure, etc.) 4

What does the CBP Toolbox offer?• Test methods and reference data

– Leaching assessment (EPA 1313, 1314, 1315, 1316)*

– Physical and chemical properties**

• Source-term Models

– STADIUM (SIMCO Technologies, Inc.)

• Ionic transport/reactions in saturated and unsaturated concrete

• Focus on durability and structural performance

– LeachXS/ORCHESTRA (Vanderbilt/ECN/NRG/HvdS)

• Geochemical, speciation-based reactive mass transport

• Focus on leaching and chemical performance

• CBP Generic Dynamic Link Library and GoldSim

– Probabilistic analysis using Monte Carlo simulation

– Integration with broader PA scenario modeling

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* These EPA Methods are available in SW-846

(http://www3.epa.gov/epawaste/hazard/testmethods/sw846/new_meth.htm)

** SIMCO, VU/ECN, & SRNL provide many ASTM and internal methods for material characterization

Why use CBP Tools?• Robust consideration of material properties, scenarios, and

aging/degradation processes

– Physical scenarios – from intact monolith (limited cracking/water interface), to percolation with radial diffusion (extensive cracking), to dual regime (rubblized)

– Multiple material layers (and variations within layers) and dimensions

– Coupled processes (as needed) of chloride/sulfate attack, oxidation, carbonation, and leaching (and aging)

• Release estimation basis that reflects current state-of-the-science, rather than gross over-simplification that results in many orders-of-magnitude uncertainty and over-estimation of release

– Conforms with “realistic case + uncertainty” assessments

– Provides basis for evaluating potential system design enhancements and waste loading limits

– Provides basis for performance monitoring

• Software Quality Assurance consistent with NQA-1 and DOE Order 414.1D

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• SRNL Experimental Results• Saltstone/ Cast Stone Tc Speciation / Mobility Studies

(CBP-TR-2014-005 / SRNL-STI-2014-00399)

• Unsaturated Hydraulic Conductivity in Fractured Materials (SRNL-STI-2014-00367 / WM2015 Paper)

• Cementitious Materials Phase Characterization (CBP-TR-2014-004 / SRNL-STI-2014-00397, Rev.1)

• SIMCO Technologies Experimental Results• Exposure Studies of DOE Cementitious Barriers (CBP-TR-2015-001)

• Transport Properties of Damaged CM (CBP-TR-2015-002)

• VU/CRESP Experimental Results• Cast Stone characterization & evaluation for Hanford (Draft reports

in review)

• Gas phase reactive species ingress (CO2, O2) (PhD dissertation in progress and journal manuscript)

Experimental Program Highlights

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SRNL Experimental Programs

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Oxidation

Front~ 38 mm

Mixed Oxidation States / Oxidation Front (130 days)Redox Sensitive (Tc/Cr) Oxidation Studies

• Contaminant specific oxidation fronts

identified by depth-discrete sampling

• Leachable and non-leachable Tc-99

fractions coexist

• Leaching in water without prior aging

may not be conservative

Mineralogy Studies

• XRD studies enables more accurate

long-term phase evolution

Hydraulic Property Characterization

• Method development for unsaturated

and fractured cementitious materials

• i

SIMCO Experimental & Model Development

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Experimental work:� Concrete mixtures characterization

� Monitoring of samples in aggressive

environments

� Physical damage characterization on

concrete

Model development:� Sulfate attack

� Carbonation

� Relationship between damage level

and concrete properties

FY14 Vanderbilt Experimental / Model Development

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Low Ca fly ash replacement

(M45-02)

Ca solubility lower in

carbonated material

Leaching Environmental Assessment Framework

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• Key foundation for new EPA regulations and

guidance on: disposal of coal combustion

residues; use of coal fly ash in concrete; waste

treatment and disposal; site remediation;

beneficial use of secondary materials –

EPA guidance planned to be issued in 2016

• Provides basis for international use of LEAF

(European Union, Australia, China, Israel)

• EPA 600/R-14/061

– Leaching Assessment Fundamentals

– 10 Cases of Large-scale Field Analysis Coupled

with Laboratory Testing For 7 Materials –

field validation

– Recommendations for Use of LEAF EPA 600/R-14/061

LEAF Leaching Methods*Method 1313 – Liquid-Solid Partitioning as a Function of Eluate pH

using a Parallel Batch Procedure

Method 1314 – Liquid-Solid Partitioning as a Function of Liquid-Solid Ratio (L/S) using an Up-flow Percolation Column Procedure

Method 1315 – Mass Transfer Rates in Monolithic and Compacted Granular Materials using a Semi-dynamic Tank Leaching Procedure

Method 1316 – Liquid-Solid Partitioning as a Function of Liquid-Solid Ratio using a Parallel Batch Procedure

*Posted to SW-846 as “New Methods” August 2013

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Example Data Sets Available

• CBP/CRESP -- EPA 1313 & 1314 -- 3 Cast Stone compositions (Blends 6, 19, 21; not including Tc) and component materials (e.g., blast furnace slag, fly ash)

• PNNL – EPA 1315 -- Range of Cast Stone compositions

– Long-term leaching w/DI water & synthetic Hanford groundwater

• CBP/CRESP – Saturation-Relative Humidity relationships

• SRNL & SIMCO – Leaching data and oxidation information available on analogous materials (e.g., surrogate wasteforms and Saltstone)

• CBP/CRESP, PNNL, SIMCO & SRNL – Wasteform, concrete, and SCM characterization data

• CBP/CRESP – XRD/SEM analysis of microconcretes (with fly ash) and Cast Stone under carbonation and oxidation

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CBP Software Toolbox Components

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DRAFT FOR REVIEW 15LXO = LeachXS/ORCHESTRA

CBP Software Toolbox Capabilities

LeachXS/ORCHESTRA

• Leaching of major,

trace & radionuclide

constituents

• Chemical evolution

(pH, redox, etc.)

• Transport (diffusion

and advection),

changes in pore

structure

• Initial and evolving

cracks and impact on

transport

STADIUM

• Transport of

chemical species

• Formation of

deleterious

minerals

• Alteration to

concrete

microstructure

• Capillary flow

• Temperature

effects

• Multi-layer

capabilities LXO Percolation

with Radial

Diffusion (cracked)

CBP Software

Toolbox

Version 3.0LXO Tank/Vault

Carbonation/

Oxidation

STADIUM

Carbonation

STADIUM

Surface Fracture

LeachXS Monolith DiffusionIntact Material with Limited Cracking

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• Laboratory and field

simulations

• Variable water contacting

sequence, chemistry

• Saturated or unsaturated

• Carbonation and

oxidation ingress (gas &

liquid)

• Sulfate attack with

leaching

Percolation with Radial DiffusionPercolation with Extensive Cracking

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• Laboratory and

field simulations

• Cracked materials

or packed beds

(e.g., wasteforms,

tank closure)

• Effects of

preferential flow

• Variable water flow

rate, chemistry

Percolation with Mobile-Immobile ZonesPercolation through Rubblized Material

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• Laboratory and field

simulations

• Variable water flow

rate, chemistry

• Effects of preferential

flow (e.g., grouted

materials,

contaminated soils)

• CBP Software Toolbox Version 3.0 with new and enhanced modules• Added Carbonation/Oxidation (LXO) – replaced Carbonation (LXO)

• Enhanced Sulfate Attack (LXO & STADIUM)

• Added Carbonation (STADIUM)

• Added Surface Fracture (STADIUM)

• Transport Properties (SRNL)

• Three CBP User Workshops Version 2.0 (~65 Attendees)• Hanford Site

• NIST/NRC

• Savannah River Site

• Emerging DOE issues identified at workshops and meetings incorporated into CBP Programs• ASR, dual mechanisms, acidic soil, mercury management

Software Program Highlights

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• DOE – Savannah River Field Office• Direct Saltstone PA Support (SRNL-STI-2013-00118)

• CBP Software Toolbox Release and Training

• Consulting on Saltstone Waste forms and Future Disposal Designs

– Higher sulfate concentrations

– Interior protective coatings

– Experimental plans

• Saltstone Oxidation Studies & Characterization

• DOE – Hanford Office of River Protection • CBP Software Toolbox Release and Training

• Program review and consulting on Integrated Disposal Facility

• Cast Stone Oxidation Studies & Characterization and Modeling

CBP Benefits: DOE Mission Direct Support

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CBP Toolbox Version 3.0

Release – late 2015

- SQA documentation consistent with NQA-1 and DOE Order 414.1D

- LXO Monolith w/carbonation, oxidation, leaching

- Enhancements for other LXO models

- STADIUM enhanced sulfate attack, carbonation, and surface fracture models

- Verification & validation for multiple models

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CBP Software Toolbox

Versions 3.0

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CRESP-Vanderbilt/ ECN/NRG/HvdS

ORCHESTRA Core(a,b)

• Kernel (Java)

• Chemical Equilibrium(d)

• Transport (e.g., diffusion)

LeachXS Core(a,b)

• Data Import/Export

• Data Analysis

• Graphics

Laboratory Methods(c)

• pH Dependent (EPA 1313)

• Percolation Column (EPA 1314)

• Mass Transfer (EPA 1315)

• Batch L/S (EPA 1316)

Virtual Materials(b)

• Saltstone + SRS Vault concretes

• Cast Stone

• Portland cement

• SCMs (fly ash, slag, etc.)

SIMCO Technologies

STADIUM Core(e)

• Chemical Equilibrium(d)

• Transport Solver

Characterization Methods(f)

• Mechanical properties

• Chloride resistance

• Potential for ASR

• Others

Characterized Materials

• SRS Vault concretes

• Standard concretes

CBP Toolbox

(GoldSim)(a)

CBP DLL(a,b)

(Joint with VU)

Mesh2D(a,b)

FlowXL(a,b)

Legenda. Software Documentation

b. Software Quality Assurance (SQA) Documentation

c. EPA/LEAF Methods and QA Documentation (SW846)

d. Literature + internal data

e. Patented

f. Published methods (e.g., ASTM)

SRNL

STADIUM Models(a)

• Sulfate/chloride ingress

• Carbonation

• Surface fracture

LeachXS/ORCHESTRA Models• Laboratory methods (EPA/LEAF) (c)

• Sulfate attack prediction(a,b)

• Carbonation/oxidation prediction(a,b)

• Percolation with Radial Diffusion(a)

CBP Software QA Summary

Timeline FY12-18

FY14 ACCOMPLISHMENTS 1

CBP Toolbox V-2.0/

Workshops • LXO Carbonation

• LXO Dual Regime

• STADIUM Chloride

• CBP/ASCEM

Integrated Demo

Development

FY12

ACCOMPLISHMENTS

CBP Toolbox V-1.0/

Workshops • STADIUM Sulfate

Attack (SA)

• LXO Sulfate Attack

2012 2013 2014 2015 2016 2017 2018

FY15 MILESTONE 1

CBP Toolbox V-3.0/

Workshops• STADIUM Carbonation

• STADIUM SA Surf. Frac.

• LXO Oxidation& Gap Flow

• SRNL Transport Prop.

• Uncertainty Framework

FY17 MILESTONE 1

CBP Toolbox V-5.0• NIST CM Additions (SA

& Carbonation)

• SRNL Tc Oxidation

• Alkali Silica Reaction

(ASR)

FY16 MILESTONE 1

CBP Toolbox V-4.0• NIST Cement. Microprobe (CM)

• STADIUM SA Variations

• SRNL Trans. Prop. & Flow

• LXO GAP Flow

FY18 MILESTONE 1

CBP Toolbox V-6.0• Dual Mechanisms

• NIST CM Enhancements

• Acidic Soil Exposure

• Uncertainty Framework

FY15 MILESTONE 2

CBP/ASCEM Demo – Phase 1

FY16 MILESTONE 2

CBP/ASCEM Demo – Phase 2

FY17 MILESTONE 2

CBP/ASCEM

Demo – Phase 3

FY18 MILESTONE 2

CBP/ASCEM Demo – Phase 4

FY14 ACCOMPLISHMENTS 2

Experimental Studies • Tc Oxidation Leaching

• CM Phase Characterization

FY15 MILESTONE 3

Experimental

Studies

• Tc Oxidation Rate

• Carbonation Rate

• Method Dev. for

Hydraulic Cond. in

Fractured

MaterialsFY16 MILESTONE 3

Experimental Studies

• ASR

• Oxidation/carbonation

FY17 MILESTONE 3

Exp. Studies

ASR

Cont’d

FY18 MILESTONE 3

Experimental

StudiesAcidic Soil Exposure

Cont’d

Next Steps• Complete Software Quality Assurance including V&V

– LeachXS including Virtual Materials

– ORCHESTRA including carbonation/oxidation model

– STADIUM including carbonation and surface fracture models

• Examine relative effects of different extents of initial cracking

• Revise scenarios to reflect IDF PA sensitivity cases

• Carry out longer-term release simulations

• Uncertainty assessment (parameter and model uncertainty)

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